In order to be certified for acceptance with a given (satellite) communication system, the directivity pattern of an antenna relative to a target (e.g., satellite) must conform with prescribed main lobe and sidelobe characteristics. Where the antenna is to be installed at a fixed, land-based location, and there are no restrictions on the physical parameters and cost of the antenna, satisfying a given performance specification may be readily accomplished by suitable design of a conventional (parabolic) dish antenna and associated monopulse hardware configuration. However, where the environment in which the antenna is to deployed is mobile and potentially hostile, a variety of physical parameters come into play, which effectively negate the use of a large dish and its associated beam steering components.
For example, in a tactical (mobile) environment, where detection and therefore survivability of a communication system may depend upon the effective profile or observable footprint of the antenna, it is highly desirable to make the antenna as small as possible. However, as the size of the antenna is reduced, so is its available energy collecting aperture. A further complication is the fact that it may be necessary to dynamically position or orient the antenna, in order to follow or track a (low earth orbit) satellite. Even if a reduced diameter dish architecture is employed, its moment of inertia and observable profile is further enlarged by the auxiliary (azimuth and elevation sum and difference horns) and waveguide and stripline `plumbing` of the associated (monopulse) tracking control subsystem. Moreover, should it be necessary to change the operational parameters of such a dish-based architecture, major disassembly and retrofitting of its associated waveguide hardware is required.